1 ;;;; This file implements the IR1 optimization phase of the compiler.
2 ;;;; IR1 optimization is a grab-bag of optimizations that don't make
3 ;;;; major changes to the block-level control flow and don't use flow
4 ;;;; analysis. These optimizations can mostly be classified as
5 ;;;; "meta-evaluation", but there is a sizable top-down component as
8 ;;;; This software is part of the SBCL system. See the README file for
11 ;;;; This software is derived from the CMU CL system, which was
12 ;;;; written at Carnegie Mellon University and released into the
13 ;;;; public domain. The software is in the public domain and is
14 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
15 ;;;; files for more information.
19 ;;;; interface for obtaining results of constant folding
21 ;;; Return true for a CONTINUATION whose sole use is a reference to a
23 (defun constant-continuation-p (thing)
24 (and (continuation-p thing)
25 (let ((use (continuation-use thing)))
27 (constant-p (ref-leaf use))))))
29 ;;; Return the constant value for a continuation whose only use is a
31 (declaim (ftype (function (continuation) t) continuation-value))
32 (defun continuation-value (cont)
33 (aver (constant-continuation-p cont))
34 (constant-value (ref-leaf (continuation-use cont))))
36 ;;;; interface for obtaining results of type inference
38 ;;; Return a (possibly values) type that describes what we have proven
39 ;;; about the type of Cont without taking any type assertions into
40 ;;; consideration. This is just the union of the NODE-DERIVED-TYPE of
41 ;;; all the uses. Most often people use CONTINUATION-DERIVED-TYPE or
42 ;;; CONTINUATION-TYPE instead of using this function directly.
43 (defun continuation-proven-type (cont)
44 (declare (type continuation cont))
45 (ecase (continuation-kind cont)
46 ((:block-start :deleted-block-start)
47 (let ((uses (block-start-uses (continuation-block cont))))
49 (do ((res (node-derived-type (first uses))
50 (values-type-union (node-derived-type (first current))
52 (current (rest uses) (rest current)))
56 (node-derived-type (continuation-use cont)))))
58 ;;; Our best guess for the type of this continuation's value. Note
59 ;;; that this may be VALUES or FUNCTION type, which cannot be passed
60 ;;; as an argument to the normal type operations. See
61 ;;; CONTINUATION-TYPE. This may be called on deleted continuations,
62 ;;; always returning *.
64 ;;; What we do is call CONTINUATION-PROVEN-TYPE and check whether the
65 ;;; result is a subtype of the assertion. If so, return the proven
66 ;;; type and set TYPE-CHECK to nil. Otherwise, return the intersection
67 ;;; of the asserted and proven types, and set TYPE-CHECK T. If
68 ;;; TYPE-CHECK already has a non-null value, then preserve it. Only in
69 ;;; the somewhat unusual circumstance of a newly discovered assertion
70 ;;; will we change TYPE-CHECK from NIL to T.
72 ;;; The result value is cached in the CONTINUATION-%DERIVED-TYPE slot.
73 ;;; If the slot is true, just return that value, otherwise recompute
74 ;;; and stash the value there.
75 #!-sb-fluid (declaim (inline continuation-derived-type))
76 (defun continuation-derived-type (cont)
77 (declare (type continuation cont))
78 (or (continuation-%derived-type cont)
79 (%continuation-derived-type cont)))
80 (defun %continuation-derived-type (cont)
81 (declare (type continuation cont))
82 (let ((proven (continuation-proven-type cont))
83 (asserted (continuation-asserted-type cont)))
84 (cond ((values-subtypep proven asserted)
85 (setf (continuation-%type-check cont) nil)
86 (setf (continuation-%derived-type cont) proven))
87 ((and (values-subtypep proven (specifier-type 'function))
88 (values-subtypep asserted (specifier-type 'function)))
89 ;; It's physically impossible for a runtime type check to
90 ;; distinguish between the various subtypes of FUNCTION, so
91 ;; it'd be pointless to do more type checks here.
92 (setf (continuation-%type-check cont) nil)
93 (setf (continuation-%derived-type cont)
94 ;; FIXME: This should depend on optimization
95 ;; policy. This is for SPEED > SAFETY:
96 #+nil (values-type-intersection asserted proven)
97 ;; and this is for SAFETY >= SPEED:
100 (unless (or (continuation-%type-check cont)
101 (not (continuation-dest cont))
102 (eq asserted *universal-type*))
103 (setf (continuation-%type-check cont) t))
105 (setf (continuation-%derived-type cont)
106 (values-type-intersection asserted proven))))))
108 ;;; Call CONTINUATION-DERIVED-TYPE to make sure the slot is up to
109 ;;; date, then return it.
110 #!-sb-fluid (declaim (inline continuation-type-check))
111 (defun continuation-type-check (cont)
112 (declare (type continuation cont))
113 (continuation-derived-type cont)
114 (continuation-%type-check cont))
116 ;;; Return the derived type for CONT's first value. This is guaranteed
117 ;;; not to be a VALUES or FUNCTION type.
118 (declaim (ftype (function (continuation) ctype) continuation-type))
119 (defun continuation-type (cont)
120 (single-value-type (continuation-derived-type cont)))
122 ;;;; interface routines used by optimizers
124 ;;; This function is called by optimizers to indicate that something
125 ;;; interesting has happened to the value of Cont. Optimizers must
126 ;;; make sure that they don't call for reoptimization when nothing has
127 ;;; happened, since optimization will fail to terminate.
129 ;;; We clear any cached type for the continuation and set the
130 ;;; reoptimize flags on everything in sight, unless the continuation
131 ;;; is deleted (in which case we do nothing.)
133 ;;; Since this can get called during IR1 conversion, we have to be
134 ;;; careful not to fly into space when the Dest's Prev is missing.
135 (defun reoptimize-continuation (cont)
136 (declare (type continuation cont))
137 (unless (member (continuation-kind cont) '(:deleted :unused))
138 (setf (continuation-%derived-type cont) nil)
139 (let ((dest (continuation-dest cont)))
141 (setf (continuation-reoptimize cont) t)
142 (setf (node-reoptimize dest) t)
143 (let ((prev (node-prev dest)))
145 (let* ((block (continuation-block prev))
146 (component (block-component block)))
147 (when (typep dest 'cif)
148 (setf (block-test-modified block) t))
149 (setf (block-reoptimize block) t)
150 (setf (component-reoptimize component) t))))))
152 (setf (block-type-check (node-block node)) t)))
155 ;;; Annotate Node to indicate that its result has been proven to be
156 ;;; typep to RType. After IR1 conversion has happened, this is the
157 ;;; only correct way to supply information discovered about a node's
158 ;;; type. If you screw with the Node-Derived-Type directly, then
159 ;;; information may be lost and reoptimization may not happen.
161 ;;; What we do is intersect Rtype with Node's Derived-Type. If the
162 ;;; intersection is different from the old type, then we do a
163 ;;; Reoptimize-Continuation on the Node-Cont.
164 (defun derive-node-type (node rtype)
165 (declare (type node node) (type ctype rtype))
166 (let ((node-type (node-derived-type node)))
167 (unless (eq node-type rtype)
168 (let ((int (values-type-intersection node-type rtype)))
169 (when (type/= node-type int)
170 (when (and *check-consistency*
171 (eq int *empty-type*)
172 (not (eq rtype *empty-type*)))
173 (let ((*compiler-error-context* node))
175 "New inferred type ~S conflicts with old type:~
176 ~% ~S~%*** possible internal error? Please report this."
177 (type-specifier rtype) (type-specifier node-type))))
178 (setf (node-derived-type node) int)
179 (reoptimize-continuation (node-cont node))))))
182 ;;; This is similar to DERIVE-NODE-TYPE, but asserts that it is an
183 ;;; error for CONT's value not to be TYPEP to TYPE. If we improve the
184 ;;; assertion, we set TYPE-CHECK and TYPE-ASSERTED to guarantee that
185 ;;; the new assertion will be checked.
186 (defun assert-continuation-type (cont type)
187 (declare (type continuation cont) (type ctype type))
188 (let ((cont-type (continuation-asserted-type cont)))
189 (unless (eq cont-type type)
190 (let ((int (values-type-intersection cont-type type)))
191 (when (type/= cont-type int)
192 (setf (continuation-asserted-type cont) int)
194 (setf (block-attributep (block-flags (node-block node))
195 type-check type-asserted)
197 (reoptimize-continuation cont)))))
200 ;;; Assert that CALL is to a function of the specified TYPE. It is
201 ;;; assumed that the call is legal and has only constants in the
202 ;;; keyword positions.
203 (defun assert-call-type (call type)
204 (declare (type combination call) (type fun-type type))
205 (derive-node-type call (fun-type-returns type))
206 (let ((args (combination-args call)))
207 (dolist (req (fun-type-required type))
208 (when (null args) (return-from assert-call-type))
209 (let ((arg (pop args)))
210 (assert-continuation-type arg req)))
211 (dolist (opt (fun-type-optional type))
212 (when (null args) (return-from assert-call-type))
213 (let ((arg (pop args)))
214 (assert-continuation-type arg opt)))
216 (let ((rest (fun-type-rest type)))
219 (assert-continuation-type arg rest))))
221 (dolist (key (fun-type-keywords type))
222 (let ((name (key-info-name key)))
223 (do ((arg args (cddr arg)))
225 (when (eq (continuation-value (first arg)) name)
226 (assert-continuation-type
227 (second arg) (key-info-type key)))))))
232 ;;; Do one forward pass over COMPONENT, deleting unreachable blocks
233 ;;; and doing IR1 optimizations. We can ignore all blocks that don't
234 ;;; have the REOPTIMIZE flag set. If COMPONENT-REOPTIMIZE is true when
235 ;;; we are done, then another iteration would be beneficial.
237 ;;; We delete blocks when there is either no predecessor or the block
238 ;;; is in a lambda that has been deleted. These blocks would
239 ;;; eventually be deleted by DFO recomputation, but doing it here
240 ;;; immediately makes the effect available to IR1 optimization.
241 (defun ir1-optimize (component)
242 (declare (type component component))
243 (setf (component-reoptimize component) nil)
244 (do-blocks (block component)
246 ((or (block-delete-p block)
247 (null (block-pred block))
248 (eq (functional-kind (block-home-lambda block)) :deleted))
249 (delete-block block))
252 (let ((succ (block-succ block)))
253 (unless (and succ (null (rest succ)))
256 (let ((last (block-last block)))
259 (flush-dest (if-test last))
260 (when (unlink-node last)
263 (when (maybe-delete-exit last)
266 (unless (join-successor-if-possible block)
269 (when (and (block-reoptimize block) (block-component block))
270 (aver (not (block-delete-p block)))
271 (ir1-optimize-block block))
273 (when (and (block-flush-p block) (block-component block))
274 (aver (not (block-delete-p block)))
275 (flush-dead-code block)))))
279 ;;; Loop over the nodes in BLOCK, looking for stuff that needs to be
280 ;;; optimized. We dispatch off of the type of each node with its
281 ;;; reoptimize flag set:
283 ;;; -- With a COMBINATION, we call PROPAGATE-FUN-CHANGE whenever
284 ;;; the function changes, and call IR1-OPTIMIZE-COMBINATION if any
285 ;;; argument changes.
286 ;;; -- With an EXIT, we derive the node's type from the VALUE's type.
287 ;;; We don't propagate CONT's assertion to the VALUE, since if we
288 ;;; did, this would move the checking of CONT's assertion to the
289 ;;; exit. This wouldn't work with CATCH and UWP, where the EXIT
290 ;;; node is just a placeholder for the actual unknown exit.
292 ;;; Note that we clear the node & block reoptimize flags *before*
293 ;;; doing the optimization. This ensures that the node or block will
294 ;;; be reoptimized if necessary. We leave the NODE-OPTIMIZE flag set
295 ;;; going into IR1-OPTIMIZE-RETURN, since IR1-OPTIMIZE-RETURN wants to
296 ;;; clear the flag itself.
297 (defun ir1-optimize-block (block)
298 (declare (type cblock block))
299 (setf (block-reoptimize block) nil)
300 (do-nodes (node cont block :restart-p t)
301 (when (node-reoptimize node)
302 (setf (node-reoptimize node) nil)
306 (ir1-optimize-combination node))
308 (ir1-optimize-if node))
310 (setf (node-reoptimize node) t)
311 (ir1-optimize-return node))
313 (ir1-optimize-mv-combination node))
315 (let ((value (exit-value node)))
317 (derive-node-type node (continuation-derived-type value)))))
319 (ir1-optimize-set node)))))
322 ;;; Try to join with a successor block. If we succeed, we return true,
325 ;;; We cannot combine with a successor block if:
326 ;;; 1. The successor has more than one predecessor.
327 ;;; 2. The last node's CONT is also used somewhere else.
328 ;;; 3. The successor is the current block (infinite loop).
329 ;;; 4. The next block has a different cleanup, and thus we may want
330 ;;; to insert cleanup code between the two blocks at some point.
331 ;;; 5. The next block has a different home lambda, and thus the
332 ;;; control transfer is a non-local exit.
334 ;;; Joining is easy when the successor's START continuation is the
335 ;;; same from our LAST's CONT. If they differ, then we can still join
336 ;;; when the last continuation has no next and the next continuation
337 ;;; has no uses. In this case, we replace the next continuation with
338 ;;; the last before joining the blocks.
339 (defun join-successor-if-possible (block)
340 (declare (type cblock block))
341 (let ((next (first (block-succ block))))
342 (when (block-start next)
343 (let* ((last (block-last block))
344 (last-cont (node-cont last))
345 (next-cont (block-start next)))
346 (cond ((or (rest (block-pred next))
347 (not (eq (continuation-use last-cont) last))
349 (not (eq (block-end-cleanup block)
350 (block-start-cleanup next)))
351 (not (eq (block-home-lambda block)
352 (block-home-lambda next))))
354 ((eq last-cont next-cont)
355 (join-blocks block next)
357 ((and (null (block-start-uses next))
358 (eq (continuation-kind last-cont) :inside-block))
359 (let ((next-node (continuation-next next-cont)))
360 ;; If NEXT-CONT does have a dest, it must be
361 ;; unreachable, since there are no uses.
362 ;; DELETE-CONTINUATION will mark the dest block as
363 ;; DELETE-P [and also this block, unless it is no
364 ;; longer backward reachable from the dest block.]
365 (delete-continuation next-cont)
366 (setf (node-prev next-node) last-cont)
367 (setf (continuation-next last-cont) next-node)
368 (setf (block-start next) last-cont)
369 (join-blocks block next))
374 ;;; Join together two blocks which have the same ending/starting
375 ;;; continuation. The code in BLOCK2 is moved into BLOCK1 and BLOCK2
376 ;;; is deleted from the DFO. We combine the optimize flags for the two
377 ;;; blocks so that any indicated optimization gets done.
378 (defun join-blocks (block1 block2)
379 (declare (type cblock block1 block2))
380 (let* ((last (block-last block2))
381 (last-cont (node-cont last))
382 (succ (block-succ block2))
383 (start2 (block-start block2)))
384 (do ((cont start2 (node-cont (continuation-next cont))))
386 (when (eq (continuation-kind last-cont) :inside-block)
387 (setf (continuation-block last-cont) block1)))
388 (setf (continuation-block cont) block1))
390 (unlink-blocks block1 block2)
392 (unlink-blocks block2 block)
393 (link-blocks block1 block))
395 (setf (block-last block1) last)
396 (setf (continuation-kind start2) :inside-block))
398 (setf (block-flags block1)
399 (attributes-union (block-flags block1)
401 (block-attributes type-asserted test-modified)))
403 (let ((next (block-next block2))
404 (prev (block-prev block2)))
405 (setf (block-next prev) next)
406 (setf (block-prev next) prev))
410 ;;; Delete any nodes in BLOCK whose value is unused and have no
411 ;;; side-effects. We can delete sets of lexical variables when the set
412 ;;; variable has no references.
414 ;;; [### For now, don't delete potentially flushable calls when they
415 ;;; have the CALL attribute. Someday we should look at the funcitonal
416 ;;; args to determine if they have any side-effects.]
417 (defun flush-dead-code (block)
418 (declare (type cblock block))
419 (do-nodes-backwards (node cont block)
420 (unless (continuation-dest cont)
426 (let ((info (combination-kind node)))
427 (when (fun-info-p info)
428 (let ((attr (fun-info-attributes info)))
429 (when (and (ir1-attributep attr flushable)
430 (not (ir1-attributep attr call)))
431 (flush-dest (combination-fun node))
432 (dolist (arg (combination-args node))
434 (unlink-node node))))))
436 (when (eq (basic-combination-kind node) :local)
437 (let ((fun (combination-lambda node)))
438 (when (dolist (var (lambda-vars fun) t)
439 (when (or (leaf-refs var)
440 (lambda-var-sets var))
442 (flush-dest (first (basic-combination-args node)))
445 (let ((value (exit-value node)))
448 (setf (exit-value node) nil))))
450 (let ((var (set-var node)))
451 (when (and (lambda-var-p var)
452 (null (leaf-refs var)))
453 (flush-dest (set-value node))
454 (setf (basic-var-sets var)
455 (delete node (basic-var-sets var)))
456 (unlink-node node)))))))
458 (setf (block-flush-p block) nil)
461 ;;;; local call return type propagation
463 ;;; This function is called on RETURN nodes that have their REOPTIMIZE
464 ;;; flag set. It iterates over the uses of the RESULT, looking for
465 ;;; interesting stuff to update the TAIL-SET. If a use isn't a local
466 ;;; call, then we union its type together with the types of other such
467 ;;; uses. We assign to the RETURN-RESULT-TYPE the intersection of this
468 ;;; type with the RESULT's asserted type. We can make this
469 ;;; intersection now (potentially before type checking) because this
470 ;;; assertion on the result will eventually be checked (if
473 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV
474 ;;; combination, which may change the succesor of the call to be the
475 ;;; called function, and if so, checks if the call can become an
476 ;;; assignment. If we convert to an assignment, we abort, since the
477 ;;; RETURN has been deleted.
478 (defun find-result-type (node)
479 (declare (type creturn node))
480 (let ((result (return-result node)))
481 (collect ((use-union *empty-type* values-type-union))
482 (do-uses (use result)
483 (cond ((and (basic-combination-p use)
484 (eq (basic-combination-kind use) :local))
485 (aver (eq (lambda-tail-set (node-home-lambda use))
486 (lambda-tail-set (combination-lambda use))))
487 (when (combination-p use)
488 (when (nth-value 1 (maybe-convert-tail-local-call use))
489 (return-from find-result-type (values)))))
491 (use-union (node-derived-type use)))))
492 (let ((int (values-type-intersection
493 (continuation-asserted-type result)
495 (setf (return-result-type node) int))))
498 ;;; Do stuff to realize that something has changed about the value
499 ;;; delivered to a return node. Since we consider the return values of
500 ;;; all functions in the tail set to be equivalent, this amounts to
501 ;;; bringing the entire tail set up to date. We iterate over the
502 ;;; returns for all the functions in the tail set, reanalyzing them
503 ;;; all (not treating Node specially.)
505 ;;; When we are done, we check whether the new type is different from
506 ;;; the old TAIL-SET-TYPE. If so, we set the type and also reoptimize
507 ;;; all the continuations for references to functions in the tail set.
508 ;;; This will cause IR1-OPTIMIZE-COMBINATION to derive the new type as
509 ;;; the results of the calls.
510 (defun ir1-optimize-return (node)
511 (declare (type creturn node))
512 (let* ((tails (lambda-tail-set (return-lambda node)))
513 (funs (tail-set-funs tails)))
514 (collect ((res *empty-type* values-type-union))
516 (let ((return (lambda-return fun)))
518 (when (node-reoptimize return)
519 (setf (node-reoptimize return) nil)
520 (find-result-type return))
521 (res (return-result-type return)))))
523 (when (type/= (res) (tail-set-type tails))
524 (setf (tail-set-type tails) (res))
525 (dolist (fun (tail-set-funs tails))
526 (dolist (ref (leaf-refs fun))
527 (reoptimize-continuation (node-cont ref)))))))
533 ;;; If the test has multiple uses, replicate the node when possible.
534 ;;; Also check whether the predicate is known to be true or false,
535 ;;; deleting the IF node in favor of the appropriate branch when this
537 (defun ir1-optimize-if (node)
538 (declare (type cif node))
539 (let ((test (if-test node))
540 (block (node-block node)))
542 (when (and (eq (block-start block) test)
543 (eq (continuation-next test) node)
544 (rest (block-start-uses block)))
546 (when (immediately-used-p test use)
547 (convert-if-if use node)
548 (when (continuation-use test) (return)))))
550 (let* ((type (continuation-type test))
552 (cond ((constant-continuation-p test)
553 (if (continuation-value test)
554 (if-alternative node)
555 (if-consequent node)))
556 ((not (types-equal-or-intersect type (specifier-type 'null)))
557 (if-alternative node))
558 ((type= type (specifier-type 'null))
559 (if-consequent node)))))
562 (when (rest (block-succ block))
563 (unlink-blocks block victim))
564 (setf (component-reanalyze (node-component node)) t)
565 (unlink-node node))))
568 ;;; Create a new copy of an IF node that tests the value of the node
569 ;;; USE. The test must have >1 use, and must be immediately used by
570 ;;; USE. NODE must be the only node in its block (implying that
571 ;;; block-start = if-test).
573 ;;; This optimization has an effect semantically similar to the
574 ;;; source-to-source transformation:
575 ;;; (IF (IF A B C) D E) ==>
576 ;;; (IF A (IF B D E) (IF C D E))
578 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new
579 ;;; node so that dead code deletion notes will definitely not consider
580 ;;; either node to be part of the original source. One node might
581 ;;; become unreachable, resulting in a spurious note.
582 (defun convert-if-if (use node)
583 (declare (type node use) (type cif node))
584 (with-ir1-environment-from-node node
585 (let* ((block (node-block node))
586 (test (if-test node))
587 (cblock (if-consequent node))
588 (ablock (if-alternative node))
589 (use-block (node-block use))
590 (dummy-cont (make-continuation))
591 (new-cont (make-continuation))
592 (new-node (make-if :test new-cont
594 :alternative ablock))
595 (new-block (continuation-starts-block new-cont)))
596 (link-node-to-previous-continuation new-node new-cont)
597 (setf (continuation-dest new-cont) new-node)
598 (add-continuation-use new-node dummy-cont)
599 (setf (block-last new-block) new-node)
601 (unlink-blocks use-block block)
602 (delete-continuation-use use)
603 (add-continuation-use use new-cont)
604 (link-blocks use-block new-block)
606 (link-blocks new-block cblock)
607 (link-blocks new-block ablock)
609 (push "<IF Duplication>" (node-source-path node))
610 (push "<IF Duplication>" (node-source-path new-node))
612 (reoptimize-continuation test)
613 (reoptimize-continuation new-cont)
614 (setf (component-reanalyze *current-component*) t)))
617 ;;;; exit IR1 optimization
619 ;;; This function attempts to delete an exit node, returning true if
620 ;;; it deletes the block as a consequence:
621 ;;; -- If the exit is degenerate (has no Entry), then we don't do
622 ;;; anything, since there is nothing to be done.
623 ;;; -- If the exit node and its Entry have the same home lambda then
624 ;;; we know the exit is local, and can delete the exit. We change
625 ;;; uses of the Exit-Value to be uses of the original continuation,
626 ;;; then unlink the node. If the exit is to a TR context, then we
627 ;;; must do MERGE-TAIL-SETS on any local calls which delivered
628 ;;; their value to this exit.
629 ;;; -- If there is no value (as in a GO), then we skip the value
632 ;;; This function is also called by environment analysis, since it
633 ;;; wants all exits to be optimized even if normal optimization was
635 (defun maybe-delete-exit (node)
636 (declare (type exit node))
637 (let ((value (exit-value node))
638 (entry (exit-entry node))
639 (cont (node-cont node)))
641 (eq (node-home-lambda node) (node-home-lambda entry)))
642 (setf (entry-exits entry) (delete node (entry-exits entry)))
647 (when (return-p (continuation-dest cont))
649 (when (and (basic-combination-p use)
650 (eq (basic-combination-kind use) :local))
652 (substitute-continuation-uses cont value)
653 (dolist (merge (merges))
654 (merge-tail-sets merge))))))))
656 ;;;; combination IR1 optimization
658 ;;; Report as we try each transform?
660 (defvar *show-transforms-p* nil)
662 ;;; Do IR1 optimizations on a COMBINATION node.
663 (declaim (ftype (function (combination) (values)) ir1-optimize-combination))
664 (defun ir1-optimize-combination (node)
665 (when (continuation-reoptimize (basic-combination-fun node))
666 (propagate-fun-change node))
667 (let ((args (basic-combination-args node))
668 (kind (basic-combination-kind node)))
671 (let ((fun (combination-lambda node)))
672 (if (eq (functional-kind fun) :let)
673 (propagate-let-args node fun)
674 (propagate-local-call-args node fun))))
678 (setf (continuation-reoptimize arg) nil))))
682 (setf (continuation-reoptimize arg) nil)))
684 (let ((attr (fun-info-attributes kind)))
685 (when (and (ir1-attributep attr foldable)
686 ;; KLUDGE: The next test could be made more sensitive,
687 ;; only suppressing constant-folding of functions with
688 ;; CALL attributes when they're actually passed
689 ;; function arguments. -- WHN 19990918
690 (not (ir1-attributep attr call))
691 (every #'constant-continuation-p args)
692 (continuation-dest (node-cont node))
693 ;; Even if the function is foldable in principle,
694 ;; it might be one of our low-level
695 ;; implementation-specific functions. Such
696 ;; functions don't necessarily exist at runtime on
697 ;; a plain vanilla ANSI Common Lisp
698 ;; cross-compilation host, in which case the
699 ;; cross-compiler can't fold it because the
700 ;; cross-compiler doesn't know how to evaluate it.
702 (let* ((ref (continuation-use (combination-fun node)))
703 (fun-name (leaf-source-name (ref-leaf ref))))
705 (constant-fold-call node)
706 (return-from ir1-optimize-combination)))
708 (let ((fun (fun-info-derive-type kind)))
710 (let ((res (funcall fun node)))
712 (derive-node-type node res)
713 (maybe-terminate-block node nil)))))
715 (let ((fun (fun-info-optimizer kind)))
716 (unless (and fun (funcall fun node))
717 (dolist (x (fun-info-transforms kind))
719 (when *show-transforms-p*
720 (let* ((cont (basic-combination-fun node))
721 (fname (continuation-fun-name cont t)))
722 (/show "trying transform" x (transform-function x) "for" fname)))
723 (unless (ir1-transform node x)
725 (when *show-transforms-p*
726 (/show "quitting because IR1-TRANSFORM result was NIL"))
731 ;;; If CALL is to a function that doesn't return (i.e. return type is
732 ;;; NIL), then terminate the block there, and link it to the component
733 ;;; tail. We also change the call's CONT to be a dummy continuation to
734 ;;; prevent the use from confusing things.
736 ;;; Except when called during IR1 [FIXME: What does this mean? Except
737 ;;; during IR1 conversion? What about IR1 optimization?], we delete
738 ;;; the continuation if it has no other uses. (If it does have other
739 ;;; uses, we reoptimize.)
741 ;;; Termination on the basis of a continuation type assertion is
743 ;;; -- The continuation is deleted (hence the assertion is spurious), or
744 ;;; -- We are in IR1 conversion (where THE assertions are subject to
746 (defun maybe-terminate-block (call ir1-converting-not-optimizing-p)
747 (declare (type basic-combination call))
748 (let* ((block (node-block call))
749 (cont (node-cont call))
750 (tail (component-tail (block-component block)))
751 (succ (first (block-succ block))))
752 (unless (or (and (eq call (block-last block)) (eq succ tail))
753 (block-delete-p block))
754 (when (or (and (eq (continuation-asserted-type cont) *empty-type*)
755 (not (or ir1-converting-not-optimizing-p
756 (eq (continuation-kind cont) :deleted))))
757 (eq (node-derived-type call) *empty-type*))
758 (cond (ir1-converting-not-optimizing-p
759 (delete-continuation-use call)
762 (aver (and (eq (block-last block) call)
763 (eq (continuation-kind cont) :block-start))))
765 (setf (block-last block) call)
766 (link-blocks block (continuation-starts-block cont)))))
768 (node-ends-block call)
769 (delete-continuation-use call)
770 (if (eq (continuation-kind cont) :unused)
771 (delete-continuation cont)
772 (reoptimize-continuation cont))))
774 (unlink-blocks block (first (block-succ block)))
775 (setf (component-reanalyze (block-component block)) t)
776 (aver (not (block-succ block)))
777 (link-blocks block tail)
778 (add-continuation-use call (make-continuation))
781 ;;; This is called both by IR1 conversion and IR1 optimization when
782 ;;; they have verified the type signature for the call, and are
783 ;;; wondering if something should be done to special-case the call. If
784 ;;; CALL is a call to a global function, then see whether it defined
786 ;;; -- If a DEFINED-FUN should be inline expanded, then convert
787 ;;; the expansion and change the call to call it. Expansion is
788 ;;; enabled if :INLINE or if SPACE=0. If the FUNCTIONAL slot is
789 ;;; true, we never expand, since this function has already been
790 ;;; converted. Local call analysis will duplicate the definition
791 ;;; if necessary. We claim that the parent form is LABELS for
792 ;;; context declarations, since we don't want it to be considered
793 ;;; a real global function.
794 ;;; -- If it is a known function, mark it as such by setting the KIND.
796 ;;; We return the leaf referenced (NIL if not a leaf) and the
797 ;;; FUN-INFO assigned.
799 ;;; FIXME: The IR1-CONVERTING-NOT-OPTIMIZING-P argument is what the
800 ;;; old CMU CL code called IR1-P, without explanation. My (WHN
801 ;;; 2002-01-09) tentative understanding of it is that we can call this
802 ;;; operation either in initial IR1 conversion or in later IR1
803 ;;; optimization, and it tells which is which. But it would be good
804 ;;; for someone who really understands it to check whether this is
806 (defun recognize-known-call (call ir1-converting-not-optimizing-p)
807 (declare (type combination call))
808 (let* ((ref (continuation-use (basic-combination-fun call)))
809 (leaf (when (ref-p ref) (ref-leaf ref)))
810 (inlinep (if (defined-fun-p leaf)
811 (defined-fun-inlinep leaf)
814 ((eq inlinep :notinline) (values nil nil))
815 ((not (and (global-var-p leaf)
816 (eq (global-var-kind leaf) :global-function)))
821 ((nil :maybe-inline) (policy call (zerop space))))
823 (defined-fun-inline-expansion leaf)
824 (let ((fun (defined-fun-functional leaf)))
826 (and (eq inlinep :inline) (functional-kind fun))))
827 (inline-expansion-ok call))
828 (flet (;; FIXME: Is this what the old CMU CL internal documentation
829 ;; called semi-inlining? A more descriptive name would
830 ;; be nice. -- WHN 2002-01-07
832 (let ((res (ir1-convert-lambda-for-defun
833 (defined-fun-inline-expansion leaf)
835 #'ir1-convert-inline-lambda)))
836 (setf (defined-fun-functional leaf) res)
837 (change-ref-leaf ref res))))
838 (if ir1-converting-not-optimizing-p
840 (with-ir1-environment-from-node call
842 (locall-analyze-component *current-component*))))
844 (values (ref-leaf (continuation-use (basic-combination-fun call)))
847 (let ((info (info :function :info (leaf-source-name leaf))))
849 (values leaf (setf (basic-combination-kind call) info))
850 (values leaf nil)))))))
852 ;;; Check whether CALL satisfies TYPE. If so, apply the type to the
853 ;;; call, and do MAYBE-TERMINATE-BLOCK and return the values of
854 ;;; RECOGNIZE-KNOWN-CALL. If an error, set the combination kind and
855 ;;; return NIL, NIL. If the type is just FUNCTION, then skip the
856 ;;; syntax check, arg/result type processing, but still call
857 ;;; RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda,
858 ;;; and that checking is done by local call analysis.
859 (defun validate-call-type (call type ir1-converting-not-optimizing-p)
860 (declare (type combination call) (type ctype type))
861 (cond ((not (fun-type-p type))
862 (aver (multiple-value-bind (val win)
863 (csubtypep type (specifier-type 'function))
865 (recognize-known-call call ir1-converting-not-optimizing-p))
866 ((valid-fun-use call type
867 :argument-test #'always-subtypep
868 :result-test #'always-subtypep
869 ;; KLUDGE: Common Lisp is such a dynamic
870 ;; language that all we can do here in
871 ;; general is issue a STYLE-WARNING. It
872 ;; would be nice to issue a full WARNING
873 ;; in the special case of of type
874 ;; mismatches within a compilation unit
875 ;; (as in section 3.2.2.3 of the spec)
876 ;; but at least as of sbcl-0.6.11, we
877 ;; don't keep track of whether the
878 ;; mismatched data came from the same
879 ;; compilation unit, so we can't do that.
882 ;; FIXME: Actually, I think we could
883 ;; issue a full WARNING if the call
884 ;; violates a DECLAIM FTYPE.
885 :lossage-fun #'compiler-style-warn
886 :unwinnage-fun #'compiler-note)
887 (assert-call-type call type)
888 (maybe-terminate-block call ir1-converting-not-optimizing-p)
889 (recognize-known-call call ir1-converting-not-optimizing-p))
891 (setf (combination-kind call) :error)
894 ;;; This is called by IR1-OPTIMIZE when the function for a call has
895 ;;; changed. If the call is local, we try to LET-convert it, and
896 ;;; derive the result type. If it is a :FULL call, we validate it
897 ;;; against the type, which recognizes known calls, does inline
898 ;;; expansion, etc. If a call to a predicate in a non-conditional
899 ;;; position or to a function with a source transform, then we
900 ;;; reconvert the form to give IR1 another chance.
901 (defun propagate-fun-change (call)
902 (declare (type combination call))
903 (let ((*compiler-error-context* call)
904 (fun-cont (basic-combination-fun call)))
905 (setf (continuation-reoptimize fun-cont) nil)
906 (case (combination-kind call)
908 (let ((fun (combination-lambda call)))
909 (maybe-let-convert fun)
910 (unless (member (functional-kind fun) '(:let :assignment :deleted))
911 (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
913 (multiple-value-bind (leaf info)
914 (validate-call-type call (continuation-type fun-cont) nil)
915 (cond ((functional-p leaf)
916 (convert-call-if-possible
917 (continuation-use (basic-combination-fun call))
920 ((or (info :function :source-transform (leaf-source-name leaf))
922 (ir1-attributep (fun-info-attributes info)
924 (let ((dest (continuation-dest (node-cont call))))
925 (and dest (not (if-p dest))))))
926 (when (and (leaf-has-source-name-p leaf)
927 ;; FIXME: This SYMBOLP is part of a literal
928 ;; translation of a test in the old CMU CL
929 ;; source, and it's not quite clear what
930 ;; the old source meant. Did it mean "has a
931 ;; valid name"? Or did it mean "is an
932 ;; ordinary function name, not a SETF
933 ;; function"? Either way, the old CMU CL
934 ;; code probably didn't deal with SETF
935 ;; functions correctly, and neither does
936 ;; this new SBCL code, and that should be fixed.
937 (symbolp (leaf-source-name leaf)))
938 (let ((dummies (make-gensym-list (length
939 (combination-args call)))))
942 (,(leaf-source-name leaf)
946 ;;;; known function optimization
948 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for NODE,
949 ;;; FUN and ARGS. If there is already a note for NODE and TRANSFORM,
950 ;;; replace it, otherwise add a new one.
951 (defun record-optimization-failure (node transform args)
952 (declare (type combination node) (type transform transform)
953 (type (or fun-type list) args))
954 (let* ((table (component-failed-optimizations *component-being-compiled*))
955 (found (assoc transform (gethash node table))))
957 (setf (cdr found) args)
958 (push (cons transform args) (gethash node table))))
961 ;;; Attempt to transform NODE using TRANSFORM-FUNCTION, subject to the
962 ;;; call type constraint TRANSFORM-TYPE. If we are inhibited from
963 ;;; doing the transform for some reason and FLAME is true, then we
964 ;;; make a note of the message in FAILED-OPTIMIZATIONS for IR1
965 ;;; finalize to pick up. We return true if the transform failed, and
966 ;;; thus further transformation should be attempted. We return false
967 ;;; if either the transform succeeded or was aborted.
968 (defun ir1-transform (node transform)
969 (declare (type combination node) (type transform transform))
970 (let* ((type (transform-type transform))
971 (fun (transform-function transform))
972 (constrained (fun-type-p type))
973 (table (component-failed-optimizations *component-being-compiled*))
974 (flame (if (transform-important transform)
975 (policy node (>= speed inhibit-warnings))
976 (policy node (> speed inhibit-warnings))))
977 (*compiler-error-context* node))
978 (cond ((not (member (transform-when transform)
980 ;; FIXME: Make sure that there's a transform for
981 ;; (MEMBER SYMBOL ..) into MEMQ.
982 ;; FIXME: Note that when/if I make SHARE operation to shared
983 ;; constant data between objects in the system, remember that a
984 ;; SHAREd list, or other SHAREd compound object, can be processed
985 ;; recursively, so that e.g. the two lists above can share their
986 ;; '(:BOTH) tail sublists.
987 (let ((when (transform-when transform)))
988 (not (or (eq when :both)
991 ((or (not constrained)
992 (valid-fun-use node type :strict-result t))
993 (multiple-value-bind (severity args)
994 (catch 'give-up-ir1-transform
995 (transform-call node (funcall fun node))
1002 (setf (combination-kind node) :error)
1004 (apply #'compiler-warn args))
1005 (remhash node table)
1010 (record-optimization-failure node transform args))
1011 (setf (gethash node table)
1012 (remove transform (gethash node table) :key #'car)))
1015 (remhash node table)
1020 :argument-test #'types-equal-or-intersect
1021 :result-test #'values-types-equal-or-intersect))
1022 (record-optimization-failure node transform type)
1027 ;;; When we don't like an IR1 transform, we throw the severity/reason
1030 ;;; GIVE-UP-IR1-TRANSFORM is used to throw out of an IR1 transform,
1031 ;;; aborting this attempt to transform the call, but admitting the
1032 ;;; possibility that this or some other transform will later succeed.
1033 ;;; If arguments are supplied, they are format arguments for an
1034 ;;; efficiency note.
1036 ;;; ABORT-IR1-TRANSFORM is used to throw out of an IR1 transform and
1037 ;;; force a normal call to the function at run time. No further
1038 ;;; optimizations will be attempted.
1040 ;;; DELAY-IR1-TRANSFORM is used to throw out of an IR1 transform, and
1041 ;;; delay the transform on the node until later. REASONS specifies
1042 ;;; when the transform will be later retried. The :OPTIMIZE reason
1043 ;;; causes the transform to be delayed until after the current IR1
1044 ;;; optimization pass. The :CONSTRAINT reason causes the transform to
1045 ;;; be delayed until after constraint propagation.
1047 ;;; FIXME: Now (0.6.11.44) that there are 4 variants of this (GIVE-UP,
1048 ;;; ABORT, DELAY/:OPTIMIZE, DELAY/:CONSTRAINT) and we're starting to
1049 ;;; do CASE operations on the various REASON values, it might be a
1050 ;;; good idea to go OO, representing the reasons by objects, using
1051 ;;; CLOS methods on the objects instead of CASE, and (possibly) using
1052 ;;; SIGNAL instead of THROW.
1053 (declaim (ftype (function (&rest t) nil) give-up-ir1-transform))
1054 (defun give-up-ir1-transform (&rest args)
1055 (throw 'give-up-ir1-transform (values :failure args)))
1056 (defun abort-ir1-transform (&rest args)
1057 (throw 'give-up-ir1-transform (values :aborted args)))
1058 (defun delay-ir1-transform (node &rest reasons)
1059 (let ((assoc (assoc node *delayed-ir1-transforms*)))
1061 (setf *delayed-ir1-transforms*
1062 (acons node reasons *delayed-ir1-transforms*))
1063 (throw 'give-up-ir1-transform :delayed))
1065 (dolist (reason reasons)
1066 (pushnew reason (cdr assoc)))
1067 (throw 'give-up-ir1-transform :delayed)))))
1069 ;;; Clear any delayed transform with no reasons - these should have
1070 ;;; been tried in the last pass. Then remove the reason from the
1071 ;;; delayed transform reasons, and if any become empty then set
1072 ;;; reoptimize flags for the node. Return true if any transforms are
1074 (defun retry-delayed-ir1-transforms (reason)
1075 (setf *delayed-ir1-transforms*
1076 (remove-if-not #'cdr *delayed-ir1-transforms*))
1077 (let ((reoptimize nil))
1078 (dolist (assoc *delayed-ir1-transforms*)
1079 (let ((reasons (remove reason (cdr assoc))))
1080 (setf (cdr assoc) reasons)
1082 (let ((node (car assoc)))
1083 (unless (node-deleted node)
1085 (setf (node-reoptimize node) t)
1086 (let ((block (node-block node)))
1087 (setf (block-reoptimize block) t)
1088 (setf (component-reoptimize (block-component block)) t)))))))
1092 ;;; Take the lambda-expression RES, IR1 convert it in the proper
1093 ;;; environment, and then install it as the function for the call
1094 ;;; NODE. We do local call analysis so that the new function is
1095 ;;; integrated into the control flow.
1096 (defun transform-call (node res)
1097 (declare (type combination node) (list res))
1098 (with-ir1-environment-from-node node
1099 (let ((new-fun (ir1-convert-inline-lambda
1101 :debug-name "something inlined in TRANSFORM-CALL"))
1102 (ref (continuation-use (combination-fun node))))
1103 (change-ref-leaf ref new-fun)
1104 (setf (combination-kind node) :full)
1105 (locall-analyze-component *current-component*)))
1108 ;;; Replace a call to a foldable function of constant arguments with
1109 ;;; the result of evaluating the form. We insert the resulting
1110 ;;; constant node after the call, stealing the call's continuation. We
1111 ;;; give the call a continuation with no DEST, which should cause it
1112 ;;; and its arguments to go away. If there is an error during the
1113 ;;; evaluation, we give a warning and leave the call alone, making the
1114 ;;; call a :ERROR call.
1116 ;;; If there is more than one value, then we transform the call into a
1118 (defun constant-fold-call (call)
1119 (declare (type combination call))
1120 (let* ((args (mapcar #'continuation-value (combination-args call)))
1121 (ref (continuation-use (combination-fun call)))
1122 (fun-name (leaf-source-name (ref-leaf ref))))
1124 (multiple-value-bind (values win)
1125 (careful-call fun-name args call "constant folding")
1127 (setf (combination-kind call) :error)
1128 (let ((dummies (make-gensym-list (length args))))
1132 (declare (ignore ,@dummies))
1133 (values ,@(mapcar (lambda (x) `',x) values))))))))
1137 ;;;; local call optimization
1139 ;;; Propagate TYPE to LEAF and its REFS, marking things changed. If
1140 ;;; the leaf type is a function type, then just leave it alone, since
1141 ;;; TYPE is never going to be more specific than that (and
1142 ;;; TYPE-INTERSECTION would choke.)
1143 (defun propagate-to-refs (leaf type)
1144 (declare (type leaf leaf) (type ctype type))
1145 (let ((var-type (leaf-type leaf)))
1146 (unless (fun-type-p var-type)
1147 (let ((int (type-approx-intersection2 var-type type)))
1148 (when (type/= int var-type)
1149 (setf (leaf-type leaf) int)
1150 (dolist (ref (leaf-refs leaf))
1151 (derive-node-type ref int))))
1154 ;;; Figure out the type of a LET variable that has sets. We compute
1155 ;;; the union of the initial value Type and the types of all the set
1156 ;;; values and to a PROPAGATE-TO-REFS with this type.
1157 (defun propagate-from-sets (var type)
1158 (collect ((res type type-union))
1159 (dolist (set (basic-var-sets var))
1160 (res (continuation-type (set-value set)))
1161 (setf (node-reoptimize set) nil))
1162 (propagate-to-refs var (res)))
1165 ;;; If a LET variable, find the initial value's type and do
1166 ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's
1168 (defun ir1-optimize-set (node)
1169 (declare (type cset node))
1170 (let ((var (set-var node)))
1171 (when (and (lambda-var-p var) (leaf-refs var))
1172 (let ((home (lambda-var-home var)))
1173 (when (eq (functional-kind home) :let)
1174 (let ((iv (let-var-initial-value var)))
1175 (setf (continuation-reoptimize iv) nil)
1176 (propagate-from-sets var (continuation-type iv)))))))
1178 (derive-node-type node (continuation-type (set-value node)))
1181 ;;; Return true if the value of Ref will always be the same (and is
1182 ;;; thus legal to substitute.)
1183 (defun constant-reference-p (ref)
1184 (declare (type ref ref))
1185 (let ((leaf (ref-leaf ref)))
1187 ((or constant functional) t)
1189 (null (lambda-var-sets leaf)))
1191 (not (eq (defined-fun-inlinep leaf) :notinline)))
1193 (case (global-var-kind leaf)
1194 (:global-function t))))))
1196 ;;; If we have a non-set LET var with a single use, then (if possible)
1197 ;;; replace the variable reference's CONT with the arg continuation.
1198 ;;; This is inhibited when:
1199 ;;; -- CONT has other uses, or
1200 ;;; -- CONT receives multiple values, or
1201 ;;; -- the reference is in a different environment from the variable, or
1202 ;;; -- either continuation has a funky TYPE-CHECK annotation.
1203 ;;; -- the continuations have incompatible assertions, so the new asserted type
1205 ;;; -- the var's DEST has a different policy than the ARG's (think safety).
1207 ;;; We change the REF to be a reference to NIL with unused value, and
1208 ;;; let it be flushed as dead code. A side-effect of this substitution
1209 ;;; is to delete the variable.
1210 (defun substitute-single-use-continuation (arg var)
1211 (declare (type continuation arg) (type lambda-var var))
1212 (let* ((ref (first (leaf-refs var)))
1213 (cont (node-cont ref))
1214 (cont-atype (continuation-asserted-type cont))
1215 (dest (continuation-dest cont)))
1216 (when (and (eq (continuation-use cont) ref)
1218 (not (typep dest '(or creturn exit mv-combination)))
1219 (eq (node-home-lambda ref)
1220 (lambda-home (lambda-var-home var)))
1221 (member (continuation-type-check arg) '(t nil))
1222 (member (continuation-type-check cont) '(t nil))
1223 (not (eq (values-type-intersection
1225 (continuation-asserted-type arg))
1227 (eq (lexenv-policy (node-lexenv dest))
1228 (lexenv-policy (node-lexenv (continuation-dest arg)))))
1229 (aver (member (continuation-kind arg)
1230 '(:block-start :deleted-block-start :inside-block)))
1231 (assert-continuation-type arg cont-atype)
1232 (setf (node-derived-type ref) *wild-type*)
1233 (change-ref-leaf ref (find-constant nil))
1234 (substitute-continuation arg cont)
1235 (reoptimize-continuation arg)
1238 ;;; Delete a LET, removing the call and bind nodes, and warning about
1239 ;;; any unreferenced variables. Note that FLUSH-DEAD-CODE will come
1240 ;;; along right away and delete the REF and then the lambda, since we
1241 ;;; flush the FUN continuation.
1242 (defun delete-let (fun)
1243 (declare (type clambda fun))
1244 (aver (member (functional-kind fun) '(:let :mv-let)))
1245 (note-unreferenced-vars fun)
1246 (let ((call (let-combination fun)))
1247 (flush-dest (basic-combination-fun call))
1249 (unlink-node (lambda-bind fun))
1250 (setf (lambda-bind fun) nil))
1253 ;;; This function is called when one of the arguments to a LET
1254 ;;; changes. We look at each changed argument. If the corresponding
1255 ;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
1256 ;;; consider substituting for the variable, and also propagate
1257 ;;; derived-type information for the arg to all the VAR's refs.
1259 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1260 ;;; subtype of the argument's asserted type. This prevents type
1261 ;;; checking from being defeated, and also ensures that the best
1262 ;;; representation for the variable can be used.
1264 ;;; Substitution of individual references is inhibited if the
1265 ;;; reference is in a different component from the home. This can only
1266 ;;; happen with closures over top level lambda vars. In such cases,
1267 ;;; the references may have already been compiled, and thus can't be
1268 ;;; retroactively modified.
1270 ;;; If all of the variables are deleted (have no references) when we
1271 ;;; are done, then we delete the LET.
1273 ;;; Note that we are responsible for clearing the
1274 ;;; CONTINUATION-REOPTIMIZE flags.
1275 (defun propagate-let-args (call fun)
1276 (declare (type combination call) (type clambda fun))
1277 (loop for arg in (combination-args call)
1278 and var in (lambda-vars fun) do
1279 (when (and arg (continuation-reoptimize arg))
1280 (setf (continuation-reoptimize arg) nil)
1282 ((lambda-var-sets var)
1283 (propagate-from-sets var (continuation-type arg)))
1284 ((let ((use (continuation-use arg)))
1286 (let ((leaf (ref-leaf use)))
1287 (when (and (constant-reference-p use)
1288 (values-subtypep (leaf-type leaf)
1289 (continuation-asserted-type arg)))
1290 (propagate-to-refs var (continuation-type arg))
1291 (let ((use-component (node-component use)))
1294 (cond ((eq (node-component ref) use-component)
1297 (aver (lambda-toplevelish-p (lambda-home fun)))
1301 ((and (null (rest (leaf-refs var)))
1302 (substitute-single-use-continuation arg var)))
1304 (propagate-to-refs var (continuation-type arg))))))
1306 (when (every #'null (combination-args call))
1311 ;;; This function is called when one of the args to a non-LET local
1312 ;;; call changes. For each changed argument corresponding to an unset
1313 ;;; variable, we compute the union of the types across all calls and
1314 ;;; propagate this type information to the var's refs.
1316 ;;; If the function has an XEP, then we don't do anything, since we
1317 ;;; won't discover anything.
1319 ;;; We can clear the Continuation-Reoptimize flags for arguments in
1320 ;;; all calls corresponding to changed arguments in Call, since the
1321 ;;; only use in IR1 optimization of the Reoptimize flag for local call
1322 ;;; args is right here.
1323 (defun propagate-local-call-args (call fun)
1324 (declare (type combination call) (type clambda fun))
1326 (unless (or (functional-entry-fun fun)
1327 (lambda-optional-dispatch fun))
1328 (let* ((vars (lambda-vars fun))
1329 (union (mapcar (lambda (arg var)
1331 (continuation-reoptimize arg)
1332 (null (basic-var-sets var)))
1333 (continuation-type arg)))
1334 (basic-combination-args call)
1336 (this-ref (continuation-use (basic-combination-fun call))))
1338 (dolist (arg (basic-combination-args call))
1340 (setf (continuation-reoptimize arg) nil)))
1342 (dolist (ref (leaf-refs fun))
1343 (let ((dest (continuation-dest (node-cont ref))))
1344 (unless (or (eq ref this-ref) (not dest))
1346 (mapcar (lambda (this-arg old)
1348 (setf (continuation-reoptimize this-arg) nil)
1349 (type-union (continuation-type this-arg) old)))
1350 (basic-combination-args dest)
1353 (mapc (lambda (var type)
1355 (propagate-to-refs var type)))
1360 ;;;; multiple values optimization
1362 ;;; Do stuff to notice a change to a MV combination node. There are
1363 ;;; two main branches here:
1364 ;;; -- If the call is local, then it is already a MV let, or should
1365 ;;; become one. Note that although all :LOCAL MV calls must eventually
1366 ;;; be converted to :MV-LETs, there can be a window when the call
1367 ;;; is local, but has not been LET converted yet. This is because
1368 ;;; the entry-point lambdas may have stray references (in other
1369 ;;; entry points) that have not been deleted yet.
1370 ;;; -- The call is full. This case is somewhat similar to the non-MV
1371 ;;; combination optimization: we propagate return type information and
1372 ;;; notice non-returning calls. We also have an optimization
1373 ;;; which tries to convert MV-CALLs into MV-binds.
1374 (defun ir1-optimize-mv-combination (node)
1375 (ecase (basic-combination-kind node)
1377 (let ((fun-cont (basic-combination-fun node)))
1378 (when (continuation-reoptimize fun-cont)
1379 (setf (continuation-reoptimize fun-cont) nil)
1380 (maybe-let-convert (combination-lambda node))))
1381 (setf (continuation-reoptimize (first (basic-combination-args node))) nil)
1382 (when (eq (functional-kind (combination-lambda node)) :mv-let)
1383 (unless (convert-mv-bind-to-let node)
1384 (ir1-optimize-mv-bind node))))
1386 (let* ((fun (basic-combination-fun node))
1387 (fun-changed (continuation-reoptimize fun))
1388 (args (basic-combination-args node)))
1390 (setf (continuation-reoptimize fun) nil)
1391 (let ((type (continuation-type fun)))
1392 (when (fun-type-p type)
1393 (derive-node-type node (fun-type-returns type))))
1394 (maybe-terminate-block node nil)
1395 (let ((use (continuation-use fun)))
1396 (when (and (ref-p use) (functional-p (ref-leaf use)))
1397 (convert-call-if-possible use node)
1398 (when (eq (basic-combination-kind node) :local)
1399 (maybe-let-convert (ref-leaf use))))))
1400 (unless (or (eq (basic-combination-kind node) :local)
1401 (eq (continuation-fun-name fun) '%throw))
1402 (ir1-optimize-mv-call node))
1404 (setf (continuation-reoptimize arg) nil))))
1408 ;;; Propagate derived type info from the values continuation to the
1410 (defun ir1-optimize-mv-bind (node)
1411 (declare (type mv-combination node))
1412 (let ((arg (first (basic-combination-args node)))
1413 (vars (lambda-vars (combination-lambda node))))
1414 (multiple-value-bind (types nvals)
1415 (values-types (continuation-derived-type arg))
1416 (unless (eq nvals :unknown)
1417 (mapc (lambda (var type)
1418 (if (basic-var-sets var)
1419 (propagate-from-sets var type)
1420 (propagate-to-refs var type)))
1423 (make-list (max (- (length vars) nvals) 0)
1424 :initial-element (specifier-type 'null))))))
1425 (setf (continuation-reoptimize arg) nil))
1428 ;;; If possible, convert a general MV call to an MV-BIND. We can do
1430 ;;; -- The call has only one argument, and
1431 ;;; -- The function has a known fixed number of arguments, or
1432 ;;; -- The argument yields a known fixed number of values.
1434 ;;; What we do is change the function in the MV-CALL to be a lambda
1435 ;;; that "looks like an MV bind", which allows
1436 ;;; IR1-OPTIMIZE-MV-COMBINATION to notice that this call can be
1437 ;;; converted (the next time around.) This new lambda just calls the
1438 ;;; actual function with the MV-BIND variables as arguments. Note that
1439 ;;; this new MV bind is not let-converted immediately, as there are
1440 ;;; going to be stray references from the entry-point functions until
1441 ;;; they get deleted.
1443 ;;; In order to avoid loss of argument count checking, we only do the
1444 ;;; transformation according to a known number of expected argument if
1445 ;;; safety is unimportant. We can always convert if we know the number
1446 ;;; of actual values, since the normal call that we build will still
1447 ;;; do any appropriate argument count checking.
1449 ;;; We only attempt the transformation if the called function is a
1450 ;;; constant reference. This allows us to just splice the leaf into
1451 ;;; the new function, instead of trying to somehow bind the function
1452 ;;; expression. The leaf must be constant because we are evaluating it
1453 ;;; again in a different place. This also has the effect of squelching
1454 ;;; multiple warnings when there is an argument count error.
1455 (defun ir1-optimize-mv-call (node)
1456 (let ((fun (basic-combination-fun node))
1457 (*compiler-error-context* node)
1458 (ref (continuation-use (basic-combination-fun node)))
1459 (args (basic-combination-args node)))
1461 (unless (and (ref-p ref) (constant-reference-p ref)
1462 args (null (rest args)))
1463 (return-from ir1-optimize-mv-call))
1465 (multiple-value-bind (min max)
1466 (fun-type-nargs (continuation-type fun))
1468 (multiple-value-bind (types nvals)
1469 (values-types (continuation-derived-type (first args)))
1470 (declare (ignore types))
1471 (if (eq nvals :unknown) nil nvals))))
1474 (when (and min (< total-nvals min))
1476 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1479 (setf (basic-combination-kind node) :error)
1480 (return-from ir1-optimize-mv-call))
1481 (when (and max (> total-nvals max))
1483 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1486 (setf (basic-combination-kind node) :error)
1487 (return-from ir1-optimize-mv-call)))
1489 (let ((count (cond (total-nvals)
1490 ((and (policy node (zerop safety))
1495 (with-ir1-environment-from-node node
1496 (let* ((dums (make-gensym-list count))
1498 (fun (ir1-convert-lambda
1499 `(lambda (&optional ,@dums &rest ,ignore)
1500 (declare (ignore ,ignore))
1501 (funcall ,(ref-leaf ref) ,@dums)))))
1502 (change-ref-leaf ref fun)
1503 (aver (eq (basic-combination-kind node) :full))
1504 (locall-analyze-component *current-component*)
1505 (aver (eq (basic-combination-kind node) :local)))))))))
1509 ;;; (multiple-value-bind
1518 ;;; What we actually do is convert the VALUES combination into a
1519 ;;; normal LET combination calling the original :MV-LET lambda. If
1520 ;;; there are extra args to VALUES, discard the corresponding
1521 ;;; continuations. If there are insufficient args, insert references
1523 (defun convert-mv-bind-to-let (call)
1524 (declare (type mv-combination call))
1525 (let* ((arg (first (basic-combination-args call)))
1526 (use (continuation-use arg)))
1527 (when (and (combination-p use)
1528 (eq (continuation-fun-name (combination-fun use))
1530 (let* ((fun (combination-lambda call))
1531 (vars (lambda-vars fun))
1532 (vals (combination-args use))
1533 (nvars (length vars))
1534 (nvals (length vals)))
1535 (cond ((> nvals nvars)
1536 (mapc #'flush-dest (subseq vals nvars))
1537 (setq vals (subseq vals 0 nvars)))
1539 (with-ir1-environment-from-node use
1540 (let ((node-prev (node-prev use)))
1541 (setf (node-prev use) nil)
1542 (setf (continuation-next node-prev) nil)
1543 (collect ((res vals))
1544 (loop as cont = (make-continuation use)
1545 and prev = node-prev then cont
1546 repeat (- nvars nvals)
1547 do (reference-constant prev cont nil)
1550 (link-node-to-previous-continuation use
1551 (car (last vals)))))))
1552 (setf (combination-args use) vals)
1553 (flush-dest (combination-fun use))
1554 (let ((fun-cont (basic-combination-fun call)))
1555 (setf (continuation-dest fun-cont) use)
1556 (setf (combination-fun use) fun-cont))
1557 (setf (combination-kind use) :local)
1558 (setf (functional-kind fun) :let)
1559 (flush-dest (first (basic-combination-args call)))
1562 (reoptimize-continuation (first vals)))
1563 (propagate-to-args use fun))
1567 ;;; (values-list (list x y z))
1572 ;;; In implementation, this is somewhat similar to
1573 ;;; CONVERT-MV-BIND-TO-LET. We grab the args of LIST and make them
1574 ;;; args of the VALUES-LIST call, flushing the old argument
1575 ;;; continuation (allowing the LIST to be flushed.)
1576 (defoptimizer (values-list optimizer) ((list) node)
1577 (let ((use (continuation-use list)))
1578 (when (and (combination-p use)
1579 (eq (continuation-fun-name (combination-fun use))
1581 (change-ref-leaf (continuation-use (combination-fun node))
1582 (find-free-fun 'values "in a strange place"))
1583 (setf (combination-kind node) :full)
1584 (let ((args (combination-args use)))
1586 (setf (continuation-dest arg) node))
1587 (setf (combination-args use) nil)
1589 (setf (combination-args node) args))
1592 ;;; If VALUES appears in a non-MV context, then effectively convert it
1593 ;;; to a PROG1. This allows the computation of the additional values
1594 ;;; to become dead code.
1595 (deftransform values ((&rest vals) * * :node node)
1596 (when (typep (continuation-dest (node-cont node))
1597 '(or creturn exit mv-combination))
1598 (give-up-ir1-transform))
1599 (setf (node-derived-type node) *wild-type*)
1601 (let ((dummies (make-gensym-list (length (cdr vals)))))
1602 `(lambda (val ,@dummies)
1603 (declare (ignore ,@dummies))